JWSS - Journal of Water and Soil Science

Today, the use of refined urban wastewater for agriculture is growing considerably. One of the methods for the natural treatment of wastewater is the constructed wetland. In this study, the effects of three and six days retention time on the vertical, horizontal and hybrid constructed wetland (first vertical and then horizontal) with perlite beds and Cyperus plants on the urban wastewater were investigated. In this study, horizontal wetlands were designed with 0.75 m width, 0.5 m depth and 6 m length; the vertical wetlands were designed as cylinders with a diameter of 0.7 m and the height of 1.2 m. On average, for the three days retention time, in the wetland with the vertical flow, 5the horizontal flow and the hybrid wetland, nitrate was 31.0, 36.7 and 56.3 percent, ammonium was 7.6, 32.7 and 37.8 percent, and the fecal coliform was decreased by 53.3, 93.4 and 96.9 percent, respectively. Also, during the six days retention time in the wetland with the vertical flow, the horizontal flow and the hybrid wetland, nitrate was 45.7, 58.5 and 77.5 percent, ammonium was 16.8, 75.2 and 79.4 percent, and fecal coliform was decreased by 58.0, 97.5 and 99.0 percent, respectively. Overall, the results showed that constructed wetland with perlite beds and Cyperus plants had a good function in removing pollutants, especially fecal coliform.

One of the ways to reduce the amount of wastewater pollution is the use of constructed wetlands. In this research, the performance of a hybrid constructed wetland with pumice ore and vetiver plant on urban wastewater has been investigated. Hybrid wetlands with these specifications were constructed in the vicinity of wastewater treatment at the Isfahan University of Technology. To evaluate the performance of constructed wetland the effects of three and six days of retention time on the removal efficiency were studied using a completely randomized design. On average, for three days of retention time, in the wetland with the vertical flow, the horizontal flow, and hybrid wetland, fecal coliform was 47.4, 98.3, and 99.1 percent, BOD₅ was 7.6, 20.9, and 26.9 percent, and the COD was 4.6, 40.0, and 42.7 percent decreased, respectively. Also, during the six days of retention time in the wetland with the vertical flow, the horizontal flow, and hybrid wetland, fecal coliform was 61.6, 99.3, and 99.8 percent, BOD₅ was 10.7, 29.9, and 37.4 percent, and COD was 16.0, 86.8, and 88.9 percent decreased, respectively. The combination of Pumice as a porous material with the ability to absorb the elements as well as vetiver as a plant capable of phytoremediation indicated a very suitable performance during low retention time.